Cytomegalovirus phosphoprotein 65 (pp65) peptide-HLA complex (CMV pp65-HLA)

Cytomegalovirus phosphoprotein 65 (pp65), encoded by the UL83 gene, is the most abundant tegument protein of the Human Cytomegalovirus (HCMV) and a dominant target for the host's cellular immune response [UniProt: P06725]. During infection, pp65 is processed into short peptides that are presented on the surface of infected cells by both HLA Class I (to CD8+ T cells) and HLA Class II (to CD4+ T cells) molecules [PubMed: 8642361]. These peptide-HLA complexes are critical for the recognition and elimination of CMV-infected cells by the immune system. In clinical contexts, particularly in immunocompromised transplant recipients, the failure to mount an effective T-cell response against these pp65 epitopes often leads to viral reactivation and severe clinical complications [PubMed: 24027108]. Consequently, these complexes serve as the primary target for various immunotherapeutic interventions, including adoptive cell therapies using virus-specific T cells (VSTs) and recombinant vaccines like Triplex [PubMed: 25609431, PubMed: 31533019]. Monitoring the presence and frequency of T cells specific to these complexes is also a vital biomarker for assessing immune reconstitution and the risk of CMV disease in high-risk patients.

Other names

CMV UL83pp65 antigenHuman herpesvirus 5 tegument protein UL83CMV pp65-derived peptides presented on patient HLA class I and class II moleculespp65-HLA complexCMV pp65-MHC complex

T-cell receptor (TCR) mediated recognition of the peptide-HLA complex, triggering cytotoxic T-lymphocyte (CTL) activation and subsequent lysis of CMV-infected cells [PubMed: 8642361].